U.S. Pat. No. 5,067,214 issued Nov. 26, 1991 to Christopher E. Hosmer and John F. Whaley for a Tenter Framer Apparatus and Method shows a self-lubricating bushing made of a polyamide resin.
U.S. Pat. No. 5,797,172 issued Aug. 25, 1998 to Christopher Eugene Hosmer for a Tenter Frame and Method discloses tenter frame apparatus of the type in which this invention has particular application.
Conventional self lubricating friction or wear devices such as bushings and/or plain bearings are typically composed of a metal housing in which a plain plastic bushing is inserted and secured in a manner preventing rotation of the bushing. Typically a metal shaft is carried in the interior diameter of the bushing. In the case of a tenter frame clip jaw application the currently issued bushings result in the bushing locking down on the metal shaft due to thermal expansion and the bushing wears out prematurely or it locks up preventing the desired function of the jaw.